Microneedle System for Transdermal Drug and Vaccine Delivery: Devices, Safety, and Prospects

Abstract

Microneedle (MN) delivery system has been greatly developed to deliver drugs into the skin painlessly, noninvasively, and safety. In the past several decades, various types of MNs have been developed by the newer producing techniques. Briefly, as for the morphologically, MNs can be classified into solid, coated, dissolved, and hollow MN, based on the transdermal drug delivery methods of “poke and patch,” “coat and poke,” “poke and release,” and “poke and flow,” respectively. Microneedles also have other characteristics based on the materials and structures. In addition, various manufacturing techniques have been well-developed based on the materials. In this review, the materials, structures, morphologies, and fabricating methods of MNs are summarized. A separate part of the review is used to illustrate the application of MNs to deliver vaccine, insulin, lidocaine, aspirin, and other drugs. Finally, the review ends up with a perspective on the challenges in research and development of MNs, envisioning the future development of MNs as the next generation of drug delivery system.

Progress in Microneedle-Mediated Protein Delivery

“…Then, after mold fabrication, microneedles can be replicated on it. MN masters are usually produced by techniques such as photolithography using deep X-ray lithography of Lithographie Galvanoformung Abformung [13,16] and ultraviolet (UV) lithography [17], laser ablation [18], micromilling and microgrinding [19,20], additive manufacturing [21,22], laser percussion drilling [13,16], and deep reactive ion etching (DRIE) [23]. The produced master can be re-used to make multiple molds, and each mold can be used several times for MN fabrication after appropriate cleaning.…”

“…Although a number of good fabrication techniques have been developed during recent years, hollow MNs still show some limitations. First of all, they are characterized by having possible allergic reactions in the case of metal MNs [13,14,76] and require specialized personnel and a complex pump-based set up for their injection [77]. Despite this, some studies recommend their applications in the dermatological field as well as in clinical applications for local and systemic delivery of drugs, vaccines, and cells [77][78][79].…”

“…For example, solid MNs have expensive fabrication costs and their difficult application processes are troublesome for patients [12]. Coated MNs are able to load only a small amount of drugs since they can only be applied on the surface of the MNs, while hollow MNs are characterized by a potential toxic effect because of the uncontrolled drug dose release that occurs [13,14], and they require specialized personnel and a complex set up for the injection. In addition, there are dissolving MNs, which are not able to provide prolonged release, and most of the methods are not suitable for protein stability [15].…”

Development and Application of Hot Embossing in Polymer Processing: A Review

“…The sensor showed a stable sensing performance and a relatively narrow accuracy fluctuation range within ±7% for polymeric sensors under both dynamic and static loads. Besides, we had also applied the hot embossing method for the 189,190 fabrication of a micro-needle array on PMMA substrates.…”

Parametric study of 3D printed microneedle (MN) holders for interstitial fluid (ISF) extraction

“…This technique has also been experimentally verified to assist in extraction of ISF from the dermis layer (Miller et al 2018;Taylor et al 2018;Tran et al 2018;Wang et al 2005). MNs have also been used for drug and vaccine delivery (He et al 2019;Kim et al 2012). Since MNs are minimally-invasive, compared to conventional injecting devices, they are generally easy to use and less painful for human use (Gill et al 2008;Haq et al 2009;Wang et al 2005).…”